Adjustable pot core coil for printed circuits

ABSTRACT

An adjustable two-part pot core coil, in which the inductance is adjustable by relative rotation of the two core halves about an axis of rotation with respect to which the pot components are concentric, the pot core halves being constructed to operatively receive the coil therein and having aligned central bores in which extends a centering pin carried by a centering disc disposed adjacent the upper core half, the bottom half of said core having an outwardly extending projection thereon adapted to extend into a recess in a resilient yoke arranged to retain said halves and said disc in operative positions, such yoke being constructed for noninterchangeable insertion into holes in a printed circuit plate, the coil being wound on a coil form which carries terminal pins for effecting electrical connection with such coil and a printed circuit plate.

United States Patent Inventors App]. No. Filed Patented Assignee Priority Gerhard Melndl;

Gerhard Winter, both oi Deutscher, Germany Nov. 5. 1969 July 13. 197 1 Siemens Aktlengesellschait Berlin, Germany Nov. 26, 1968 Germany P I8 ll 045.7

ADJUSTABLE POT CORE COIL FOR PRINTED 2,836,804 5/1958 Gloveret al. H 336/135 3.l97,|67 7/l965 Sturgis 336/83 UX 3,358,255 l2/l96? Digilio 336/33 FOREIGN PATENTS 1,175,256 3/1959 France 336/135 4l8,4l3 2/l967 Switzerland 336/135 Primary Examiner-Thomas J. Kozma Attorney-Hill, Sherman. Meroni, Gross & Simpson ABSTRACT: An adjustable two-part pot core coil, in which the inductance is adjustable by relative rotation of the two core halves about an axis of rotation with respect to which the pot components are concentric, the pot core halves being constructed to operatively receive the coil therein and having aligned central bores in which extends a centering pin carried by a centering disc disposed adjacent the upper core half, the bottom half of said core having an outwardly extending projection thereon adapted to extend into a recess in a resilient yoke arranged to retain said halves and said disc in operative positions, such yoke being constructed for noninterchangeable insertion into holes in a printed circuit plate, the coil being wound on a coil form which carries terminal pins for effecting electrical connection with such coil and a printed circuit plate.

ADJUSTABLE POT CORE COIL FOR PRINTED CIRCUITS BACKGROUND OF THE INVENTION The invention relates to an adjustable two-part pot core coil for printed circuits and the like, wherein the adjustment of the inductance is effected by relative rotation between the two core halves, in particular a miniature ferrite coil for communication equipment and the like.

It is an old and conventional expedient in the art to insert electrical coils into so-called pot cores consisting of ferrite material to increase the inductance. Likewise it has been heretofore proposed to effect the adjustment of the inductance value by relative rotation between two parts of the core structure and to employ a resilient yoke to urge the two parts of the core into engagement with one another, at the same time utilizing such yoke to fasten the components on a printed circuit plate.

All of such prior constructions, however, possess certain disadvantages. Of most importance is the fact that it has heretofore not been possible to reduce the overall dimensions of adjustable pot cores in the same proportions as the dimensions of the other miniaturized components employed in this field. Also, the components required in connection with the fastening and adjusting of the structure heretofore have required a relatively great amount of space.

It is heretofore the object of the invention to produce an adjustable pot core coil utilizing two magnetically operative core halves, a coil form, an adjusting device and a mounting yoke which eliminates the disadvantages inherent in previous devices, and in particular complies with the requirement for minimum dimensions.

BRIEF SUMMARY OF THE INVENTION This objective is achieved in the present invention by the utilization of a pot core coil in which the two core halves are held together and adjusted by a centering disc having a centering pin inserted in a central bore in each of the pot halves, with the bottom half of the core having a projection, and the components retained in assembled relation by a resilient yoke, which may be snapped into position, in engagement with such projection, and is suitable for noninterchangeable insertion into the mounting holes of the printed circuit plate.

This construction possesses the advantage that the two core halves are maintained in alignment at all time, particularly during the adjusting operation and that during the relative rotation of the top core half with respect to the bottom half, the latter is prevented from rotating therewith. Likewise the yoke cannot laterally slide off of the core structure and by giv ing the ends of the yoke, which are adapted to be inserted into the mounting holes of the printed circuit plate, and asymmetrical shape a noninterchangeable mounting is achieved. Further, and of particular importance is the fact that the requirement for minimum dimensions can be satisfied as the dimensions of the various components may be kept to the barest minimum.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, wherein like reference characters indicate like or corresponding parts, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. I is a sectional view of a pot core coil, taken approximately on the line l-] of FIG. 2;

FIG. 2 is a top plan view of the structure illustrated in FIG.

FIG. 3 is a transverse sectional view taken approximately on the line Ill-Ill of FIG. 4; and

FIG. 4 is a sectional view, similar to FIG. I, taken approximately on the line lV-IV of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION The lower pot core half I and upper half 3 are cooperable to receive a coil form 2 having wound thereon a coil 2', each of the core halves being provided with a central hole or bore. Cooperable with the core halves is a centering disc 4, having a centering pin 5 of a size to be received in the central holes in the respective core halves, operative to maintain the two core halves in alignment during the adjusting operation and preventing lateral movement of the cores with respect to one another.

The lower core half I is provided with asymmetric recesses la and lb which are illustrated as being shaped complementally to cooperable portions 20 and 2b of the coil form I, each of which portions are slotted as illustrated. The upstanding central portion lc of the lower core half I and corresponding central portion 3a of the upper core half 3 are provided with corresponding generally semicircular projections Id and 3b, whereby upon a rotation of of the upper core half with respect to the lower core half the projections lo and 3b may be disposed in superimposed or nonsuperimposed relationship, so that the effective inductance of the coil may be varied by the corresponding rotatlve adjustment between two core halves.

Carried by the portions 20 and 2b of the coil form 2 are respective soldering pins 8 to which the wire ends of the coil may be secured, and by the insertion of such pins into a printed circuit plate connection with the coil may be readily effected. Such pins are carried directly by the coil form 2 and may be suitably assembled therewith during the fabrication of the coil form, for example by molding therewith or suitable subsequent insertion. This construction has the advantage that immediately following the winding of the coil, the wire ends can be wrapped around the cooperable soldering pins whereby the wires will not be mixed up and improper connections thereby largely avoided. In addition, the construction enables all wires so wound to be soldered in a common dip soldering operation.

The two core halves, centering disc 4 and wound coil form are adapted to be retained in assembled relation by a yoke 6, illustrated as being constructed from strip material and adapted to be snapped into its operative position, the yoke having a recess adjacent one sidewall of the bottom core half 1 in which is disposed a projection 7 carried by such bottom half, which interlocking action insures the proper orientation of the yoke with respect to the core halves and prevents an undesired shifting of the yoke with respect thereto. In addition, such construction provides a firm anchoring of the bottom core half 1, preventing rotative movement of the upper core half 3 from being transmitted to the lower core half. Likewise, any rotative forces applied to the lower half will be transmitted to the yoke to reduce torque forces on the soldering pins 8.

As illustrated in FIGS. I, 2 and 4, the upper face of the upper core half 3 is provided with a plurality of recesses 30 which are adapted to receive projections 4a on the lower face of the centering disc 4, whereby rotative movement by the latter will be transmitted to the upper core half 3. It will also be noted from a reference to FIGS. 1 and 4 that the yoke 6 bears on the disc 4 at the central portion thereof whereby very little torque is exerted on the yoke, and in addition thereto the lower faceof the disc 4 is provided with a central recess operative to form a peripheral flange 4b which bears on the upper peripheral surface of the upper core half 3 so that the pressure applied to the assembly by the yoke 6 is transmitted from the center of the centering disc 4 to the insensitive periphery of the pot core.

Nickel silver has been found to be a particularly suitable material for the yoke 6 as it possesses excellent spring characteristics and can be readily soldered. The centering disc 4 and centering pin 5 may be constructed of plastic and preferably are molded or injected as a single piece.

Rotational adjustment of the upper core half 3 with respect to the lower half I, may be readily accomplished by applying rotative force to the centering disc 4 which in turn will be transmitted to the upper half 3 by the respective projections 4a. Rotation of the disc 4 is facilitated by means of slots 4c for the reception ofa suitable adjusting tool or key.

it will be appreciated from the above description that the construction is such that the number of components are reduced to a bare minimum and that their arrangement and assembly is such that extreme miniaturization can be achieved. For example, a structure constructed as illustrated may have a total seated height of only 7.5 mm. with a diameter of approximately 7.5 mm. whereby the dimensions of the structure are such that the volume of the latter clearly is in correspondence to and compatible with other miniaturized components with which it is to be mounted on a printed circuit plate.

It will also be appreciated that while the invention enables the fabrication of pot core coil in accordance with miniaturization techniques, that the construction is such that even with its small size a comparatively large adjusting element is presented. the centering disc 4 substantially corresponding in diameter to the maximum width of the structure, greatly facilitating adjustment operations as well as providing a rugged and durable construction.

We claim as our invention:

1. An adjustable two-part pot core coil, in which the inductance is adjustable by relative rotation of the two core halves about an axis of rotation with respect to which the pot components are concentric, in particular a miniature ferrite core for communication equipment and for utilization in printed circuits, comprising a coil, a pair of pot core halves, cooperable to operatively receive said coil therein, said halves having aligned central bores therein, a rotatable centering disc disposed adjacent the upper core half and having a centering pin extending into the central bores of said halves, the bottom half of said core having an outwardly extending projection thereon, a resilient yoke arranged to bear on said disc to retain said halves and said disc in operative positions and having a recess therein to receive said projection, said yoke being constructed for noninterchangeable insertion into holes of a printed circuit platex, said upper core half having means thereof adjacent the periphery thereof by which relative rotation of such core half relative to the bottom core half may be effected.

2. A pot core coil according to claim l, wherein said coil is wound on a coil form, the bottom core half having asymmetric recesses therein in which portions of such coil form are disposed.

3. A pot core coil according to claim 2, wherein said coil form carries terminal pins for effecting electrical connection with such coil.

4. A pot core coil according to claim 3, wherein said terminal pins are carried by portions of said coil form disposed in said asymmetric recesses.

5. A pot core coil according to claim I, wherein said yoke is engaged with said disc at the axis thereof, the latter being so constructed that pressure exerted by said yoke on said disc is transmitted to the periphery of the pot core.

6. A pot core coil according to claim 5, wherein said means on said upper core half is constructed for interlocking engagement with means on said disc, whereby rotation of said disc is transmitted to such core half, and means on said disc adjacent the periphery thereof for engagement with an adjusting for effecting rotational adjustment of said disc and such core half.

7. A pot core coil according to claim I, wherein said yoke is composed of nickel silver.

8. A pot core coil according to claim 1, wherein the centering disc is composed of plastic.

9. A pot core coil according to claim I, wherein said means on said upper core half is constructed for interlocking en agement wit means on said disc, whereby rotatlon of said tsc is transmitted to such core half.

10. A pot core coil according to claim 2, wherein said recesses are disposed at opposite sides of such core half and extend to the periphery and bottom face of such core half, said portions of said coil form disposed in such recesses having a configuration complemental thereto and having their faces flush with the bottom face of such core half. 

1. An adjustable two-part pot core coil, in which the inductance is adjustable by relative rotation of the two core halves about an axis of rotation with respect to which the pot components are concentric, in particular a miniature ferrite core for communication equipment and for utilization in printed circuits, comprising a coil, a pair of pot core halves, cooperable to operatively receive said coil therein, said halves having aligned central bores therein, a rotatable centering disc disposed adjacent the upper core half and having a centering pin extending into the central bores of said halves, the bottom half of said core having an outwardly extending projection thereon, a resilient yoke arranged to bear on said disc to retain said halves and said disc in operative positions and having a recess therein to receive said projection, said yoke being constructed for noninterchangeable insertion into holes of a printed circuit platex, said upper core half having means thereof adjacent the periphery thereof by which relative rotation of such core half relative to the bottom core half may be effeCted.
 2. A pot core coil according to claim 1, wherein said coil is wound on a coil form, the bottom core half having asymmetric recesses therein in which portions of such coil form are disposed.
 3. A pot core coil according to claim 2, wherein said coil form carries terminal pins for effecting electrical connection with such coil.
 4. A pot core coil according to claim 3, wherein said terminal pins are carried by portions of said coil form disposed in said asymmetric recesses.
 5. A pot core coil according to claim 1, wherein said yoke is engaged with said disc at the axis thereof, the latter being so constructed that pressure exerted by said yoke on said disc is transmitted to the periphery of the pot core.
 6. A pot core coil according to claim 5, wherein said means on said upper core half is constructed for interlocking engagement with means on said disc, whereby rotation of said disc is transmitted to such core half, and means on said disc adjacent the periphery thereof for engagement with an adjusting for effecting rotational adjustment of said disc and such core half.
 7. A pot core coil according to claim 1, wherein said yoke is composed of nickel silver.
 8. A pot core coil according to claim 1, wherein the centering disc is composed of plastic.
 9. A pot core coil according to claim 1, wherein said means on said upper core half is constructed for interlocking engagement with means on said disc, whereby rotation of said disc is transmitted to such core half.
 10. A pot core coil according to claim 2, wherein said recesses are disposed at opposite sides of such core half and extend to the periphery and bottom face of such core half, said portions of said coil form disposed in such recesses having a configuration complemental thereto and having their faces flush with the bottom face of such core half. 